John wesley mabden



Patented Feb. 14, 1928. V

UNITED STATES PATENT OFFICE.

JOHN WESLEY MARDEN, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO WESTING-HOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA..

PRODUCTION OF RARE-METAL POWDERS.

No Drawing. Application'flled January 3, 1928. Serial No. 610,516.

This application is a continuation in part In my improved process, Ifind it desir- 55 of my application, Serial No; 435,542, filed able toemploy, in conjunction with the re- January 6, 1921, for animprovcmentin the ducing agent, for example, magnesium, a reduction ofrare metal oxids, assigned to fluxing a ent, such as a salt, forinstance,

the Westinghouse Lamp Company. calcium c loride. This fluxing agent andThisinvention relates to the reduction of the magnesium probablyinteract to some 00 oxids, more especially oxids of the rare reex ent oform magnesium chloride and calfractory metals, particularly uranium andl m. thus providing an additional reducing thorium, by means of oth t lagent. At the same time, the magnesium In the patent applicationpreviously chloride produced by this reactionprobably f d t th th d d ibd th i o combines with the rare-metal oxide to form on prises forming amixture of the oxide of a chloride of the rare metal and magnesium themetal to be reduced and magnesium oxide. AS the chloride of the raremetal is powder i th proportions f b t 100 more easily reduced than theoxide, it is grams of the former to about gr f obvious that the raremetal is more easily the latter. This mixture is placed in a Obtained- Afeature f h mbomb. The bomb is then evacuated or prop y nt f he flflXingagent is that, durid d ith an atmosphere f hyd by ing the reaction, thecalcium chloride fuses connecting an inlet in the cap of th b b andfinally becomes a liquid which collects 20 with an convenient form ofdevice for over the rare-metal powder, the latter setforcing ydrogeninto the bomb. The air tling to the bottom of the bomb. Upon ispermitted to pass out and the hydrogen cooling, the calcium chloridesets into a very to take the place thereof, Th b b i hard mass and thusprotects the powder, thereafter sealed. Heat is applied to start uponopening of the bomb, from direct con- 25 the reaction which pro csses,without any tact Wi h the aircontinued application 0 said heat, by meansAs the process progresses, the reaction of the h at of th r action, By man of takes place in successive stages-and rather this method, after thereaction is complete, S1 Wl So that the quality of the powder pro-- theproducts thereof consist of the rare- (11108 is relatively coarse. Insubsequently 30 metal owder, magnesium oxide and magconverting thepOWdBI into the coherent C011- nesium i d t g th dition, it is foundthat a coarse powder lends The rare-metal powder is extracted byreitself to being pressed into a slug more moval of the magnesium oxideand magreadily than a fine powder. nesium by treating the mixtureseveral times The proportions of magnesium and mag- 35 with water andthen with dilute acids. The nesium chloride must of necessity dependmetal powder is then washed with water to upon the temperature to whichthe mixture remove the acid and dried by means of is heated, which oxideof uranium is used, alcohol and ether. and the like. 7 In opening thebomb. it is obvious that A specific example of the process, as apthe airwill come in contact with the reduced plied to the production of uraniumpowder metal which causes, it the metal is very is as follows. 50 gramsof u raniumroxide .95

active, the formation of oxides, etc., thereis mixed with 50 grams ofmagnesium 'powof. Furthermore, the nature of the reacder and grams ofcalcium chloride. .The;: tion and its progress within the bomb isproportions of magnesium and calcium 45 such as to produce a rare-metalpowder of-chloride should be such as to.show a 50% considerablefineness, making it difiicult to excess of the magnesium over thetheoretifilter and handle. cal quantity required by the equation. The

In order to provide a process which will ingredients are intimatelymixed and thererevent contamination of the metal powder after placed ina bomb. The bomb is fitted after its reduction and during its removalwith an inlet in the cap thereof and hydrofrom' the bomb and to obtainalso a coarser gen is passed in therethrough to displace the ma grade ofmetal powder, the rocess hereinair before the bomb is finally sealed.After after described and constituting the subject sealing, heat isapplied externally to start matter of my invention has been devised. thereaction which progresses without further application of heat, by meansof the heat of reaction. if desired, the bomb may be evacuated, or, if asuflicient excess of the reducing metal is used, it need merely besealed.

' It is desirable, in order to carry out the process successfully, thata. fairl high pressure of magnesium 'vapor be tained for,

unless this condition prevails, the magnesium and is vaporizes beforethe reduction is complete. Therefore, it is preferable, in formingthemixture, to use a 50% excess of magnesium over the theoretical quantityrequired by the equation. The reaction takes place somewhat as followsand may be represented by the following equations, uranium oxide (U0being employed as the specific example of a rare refractory oxide,

The reaction between the magnesium and calcium progresses and producesmagnesium chloride and calcium. The magnesium chloride, as indicated inequation 2, combines with uranium oxide to provide uranium chloride andmagnesium oxide and, as indicatcd in equation 3, the uranium chloride isreduced by the magne ium present and the calcium produced by the firstreaction. The first reaction does not progress any further to the rightuntil the magnesium chloride has been removed by combination withuranium oxide, as in equation 2. Upon removal of'the magnesium chloridein this manner, the reaction in equation 1 continues so that the r*actions are successfully performed and progress slowly. Because of theslowness of the progress of the reaction, a relatively coarse uraniumpowder is to duccd. During the reaction, the calcium chloride will meltand form a liquid seal over any uranium powder which is formed; thelatter, because of its higher specific gravity falling to the bottom ofthe bomb. The calcium chloride thus protects themetal powder so that,after the bomb has cooled openedup for removal of the contents, the airis prevented from coming into contact with the pure powder.

While the foregoing theory is offered as a probable explanation of theprocess by which metallic oxides are reduced, it is to be understoodthat an interpretation of my invention is not to be based on such theorywhich, although plausible in the lightof may yet prove to presentknowledge, 9 different from the actual mechanics of the reaction.

Although the method above described is applied specifically to theproduction of uranium,'it may be utilized in the production of otherrare refractory-metal powders with perhap minor modifications thereinwell known to those skilled in the art. Therefore, I contemplate anymodifications or extensions of the invention which fall within the scopeof the appended claims.

What is claimed is:

l. The method of producing rare refractory metals which comprisesheating an oxidc ot' the rare refractory metal to he formed withmagnesium and a fluxing agent.

2. The method of producing rare refractory metal powders which comprisesheating an oxide of the metal to be formed with magnesium and calciumchloride.

3. The method of producing uranium which comprises heating an oxide ofuranium with magnesium and a iiuxing agent.

-4. The method of producing uranium which comprises l'ieating an oxideof ura nium with magnesium and calcium chloride in an inert atmosphere.

-5. The method of producing uranium which comprises heating an oxide oiuranium with magnesium and calcium chloride in an atmosphere ofhydrogen.

6. The method of producing uranium powder which comprises heating anoxide of uranium powder with magnesium and calcium chloride, saidmagnesium being in excess of the theoretical quantity required by theequation.

7. The method of producing uranium powder which comprises heating anoxide of uranium owder with magnesium and calcium chlori c, saidmagnesium being in 50% excess of the theoretical quantity required bythe equation.

8. The method of producing coarse uranium powder Which comprises formingan intimate mixture of uranium oxide, magnesium and calcium chloride,placing said mixture in a bomb, providing said bomb with a hydrogenatmosphere, sealing said bomb, heating to start the reaction and aftersaid reaction is completed allowing said bomb to cool and thereafterremoving the contents thereof.

In testimony whereof, I have hereunto subscribed my name this second dayof January 1923.

JOHN WESLEY MARDEN.

